#include <DHT22.h>  // Using DHT22-specific library

// Pin definitions
#define DHTPIN 15        // DHT22 data pin
#define GAS_PIN 34       // MQ2 analog pin (ADC1_CH6)
#define SOUND_PIN 35     // Sound sensor analog pin (ADC1_CH7)

// Initialize DHT22 sensor
DHT22 dht22(DHTPIN);

// Variables for sensor readings
float temperature = 0.0;
float humidity = 0.0;
int gasValue = 0;
int soundLevel = 0;
float gasVoltage = 0.0;
float gasPPM = 0.0;

// Sound detection variables
int soundThreshold = 2000;  // Adjusted threshold for potentiometer
bool coughDetected = false;

void setup() {
  Serial.begin(115200);
  
  // Configure ADC pins
  analogReadResolution(12);  // 12-bit ADC resolution (0-4095)
  
  Serial.println("=================================");
  Serial.println("   BreathAI Sensor Monitor");
  Serial.println("=================================");
  Serial.println("Initializing sensors...");
  
  delay(2000);  // Give sensors time to stabilize
  
  Serial.println("Sensors ready!");
  Serial.println("Reading format: Temp(°C) | Humidity(%) | Gas(ppm) | Sound Level | Status");
  Serial.println("----------------------------------------------------------------------");
}

void loop() {
  readDHT22();
  readGasSensor();
  readSoundSensor();
  displayReadings();
  checkAlerts();
  delay(2000);
}

void readDHT22() {
  // Read temperature and humidity from DHT22
  temperature = dht22.getTemperature();
  humidity = dht22.getHumidity();
  
  // Check if readings are valid using isnan() function
  if (isnan(temperature) || isnan(humidity)) {
    Serial.println("ERROR: Failed to read from DHT22 sensor!");
    temperature = -999;
    humidity = -999;
  }
}

void readGasSensor() {
  gasValue = analogRead(GAS_PIN);
  gasVoltage = gasValue * (3.3 / 4095.0);
  gasPPM = mapFloat(gasValue, 0, 4095, 0, 1000);
}

void readSoundSensor() {
  soundLevel = analogRead(SOUND_PIN);
  coughDetected = (soundLevel > soundThreshold);
}

void displayReadings() {
  Serial.print("Temp: ");
  if (temperature != -999) {
    Serial.print(temperature, 1);
    Serial.print("°C");
  } else {
    Serial.print("ERROR");
  }
  
  Serial.print(" | Humidity: ");
  if (humidity != -999) {
    Serial.print(humidity, 1);
    Serial.print("%");
  } else {
    Serial.print("ERROR");
  }
  
  Serial.print(" | Gas: ");
  Serial.print(gasPPM, 0);
  Serial.print(" ppm");
  
  Serial.print(" | Sound: ");
  Serial.print(soundLevel);
  
  Serial.print(" | Status: ");
  if (coughDetected) {
    Serial.print("COUGH DETECTED!");
  } else {
    Serial.print("Normal");
  }
  Serial.println();
}

void checkAlerts() {
  bool alertTriggered = false;
  String alertMessage = "ALERT: ";
  
  if (temperature > 35.0 && temperature != -999) {
    alertMessage += "High Temp! ";
    alertTriggered = true;
  }
  
  if (humidity > 80.0 && humidity != -999) {
    alertTriggered = true;
    alertMessage += "High Humidity! ";
  }
  
  if (gasPPM > 300) {
    alertMessage += "High Gas Levels! ";
    alertTriggered = true;
  }
  
  if (coughDetected) {
    alertMessage += "Cough Activity! ";
    alertTriggered = true;
  }
  
  if (alertTriggered) {
    Serial.println("🚨 " + alertMessage);
  }
}

float mapFloat(float x, float in_min, float in_max, float out_min, float out_max) {
  return (x - in_min) * (out_max - out_min) / (in_max - in_min) + out_min;
}